ACA Wireless Technologies 2 — Questions and Answers
Question 1: Which IEEE 802.11 amendment introduced OFDMA as a key feature to improve multi-user efficiency?
- 802.11ac
- 802.11n
- 802.11ax (Correct answer)
- 802.11g
Correct answer: 802.11ax
802.11ax (Wi-Fi 6) introduced OFDMA (Orthogonal Frequency Division Multiple Access) to allow simultaneous transmission to multiple clients.
Question 2: What is the primary purpose of a BSSID in a wireless network?
- Identifies the wireless channel in use
- Uniquely identifies an access point's radio interface using its MAC address (Correct answer)
- Assigns IP addresses to wireless clients
- Specifies the encryption algorithm used
Correct answer: Uniquely identifies an access point's radio interface using its MAC address
A BSSID (Basic Service Set Identifier) is the MAC address of the AP's radio interface and uniquely identifies that BSS.
Question 3: In Aruba's architecture, which component is responsible for centralized WLAN control when using controller-based deployment?
- Aruba ClearPass
- Aruba Mobility Controller (Correct answer)
- Aruba AirWave
- Aruba Central
Correct answer: Aruba Mobility Controller
Aruba Mobility Controller acts as the centralized WLAN controller, managing APs and enforcing policies in a controller-based deployment.
Question 4: Which wireless frequency band is most susceptible to interference from microwave ovens and Bluetooth devices?
- 900 MHz
- 2.4 GHz (Correct answer)
- 5 GHz
- 6 GHz
Correct answer: 2.4 GHz
The 2.4 GHz band is heavily used by microwave ovens, Bluetooth, and other consumer devices, causing frequent interference.
Question 5: What does the term 'roaming' refer to in a wireless LAN environment?
- Scanning for available SSIDs
- A client moving between APs while maintaining network connectivity (Correct answer)
- Switching between 2.4 GHz and 5 GHz bands
- Connecting to a guest SSID automatically
Correct answer: A client moving between APs while maintaining network connectivity
Roaming is the process by which a wireless client transitions from one AP to another without losing network connectivity.
Question 6: Which authentication framework is most commonly used for enterprise wireless networks to authenticate users against a RADIUS server?
- WEP
- WPA2-Personal
- 802.1X/EAP (Correct answer)
- MAC Authentication Bypass
Correct answer: 802.1X/EAP
802.1X with EAP (Extensible Authentication Protocol) is the standard enterprise authentication framework that integrates with RADIUS servers.
Question 7: In Wi-Fi 6 (802.11ax), what is the maximum number of spatial streams supported?
- 4
- 6
- 8 (Correct answer)
- 12
Correct answer: 8
Wi-Fi 6 (802.11ax) supports up to 8 spatial streams for MIMO transmission, doubling the theoretical throughput per radio.
ACA Wireless Technologies 2
Which IEEE 802.11 amendment introduced OFDMA as a key feature to improve multi-user efficiency?